JP2004190570A - Onboard internal combustion engine having function of nitrogen enriched combustion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an onboard internal combustion engine having a function of producing a nitrogen enriched combustion, wherein generation of nitrogen oxide NO<SB>x</SB>is suppressed by supplying a nitrogen enriched gas of an appropriate nitrogen content derived from partial removal of atmospheric oxygen. <P>SOLUTION: Operation of the onboard internal combustion engine 1 is performed at a larger air-fuel ratio than the stoichiometric air-fuel ratio. The engine 1 includes a catalyst 34, a nitrogen-enriched gas generator 30, a measuring means 21, and nitrogen-enriched-gas-supply controllers 25, 35, 23. The catalyst 34 is provided in an exhaust-gas passage 15 to purify contaminants in the gas. The nitrogen-enriched-gas generator 30 generates a nitrogen-enriched gas of a high nitrogen content by partly removing oxygen in the air. The measuring means 21 measures an amount per unit time of fuel supplied into a combustion chamber 7 of the engine 1. The controllers 25, 35, 23 calculate a necessary amount of oxygen per unit time for perfectly burning the fuel in the supply amount measured by the measuring means 21, and control the supply of the gas in the amount corresponding nearly to the necessary amount of oxygen per unit time so as to meet the prescribed air-fuel ratio. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides nitrogen-enriched air having an appropriate nitrogen content by partially removing oxygen from the air to a combustion chamber of an internal combustion engine mounted on a vehicle such as an automobile or a motorcycle, thereby generating nitrogen oxides. The present invention relates to an internal combustion engine with a nitrogen-enriched combustion function that suppresses odor.
[0002]
[Prior art]
In the low-load operation range of the internal combustion engine, the throttle valve is throttled to reduce the supply amounts of fuel and air to a small amount. To avoid pumping loss due to the throttle of the throttle valve, the air-fuel ratio is reduced to a stoichiometric air-fuel ratio of 14. The operation was performed at a large air-fuel ratio such as 21 having a larger air amount than 0.8, and by increasing the gas amount, the combustion temperature was lowered, the fuel efficiency was improved, and the generation of nitrogen oxides was suppressed. .
[0003]
However, in an operation state with a large air-fuel ratio, of the oxygen in the air supplied into the combustion chamber, excess oxygen other than oxygen that causes a chemical reaction with fuel and contributes to combustion causes a chemical reaction with nitrogen in the combustion chamber. However, particularly in a high temperature state, generation of nitrogen oxides is inevitable, and exhaust purification by a three-way catalyst in the presence of excess oxygen cannot be sufficiently achieved.
[0004]
To remedy this, conventionally, there is an exhaust gas recirculation device (EGR) that introduces a part of the exhaust gas into an intake passage and recirculates the exhaust gas. The exhaust gas recirculation introduction amount was limited due to the limit and the heat resistance limit of the EGR valve, so that sufficient exhaust gas recirculation could not be performed.
[0005]
In addition, it is difficult to accurately measure inert gas components, fuel components, moisture, temperature, and the like in the exhaust gas recirculation gas, and these significantly vary depending on the running state of the vehicle and the operating state of the internal combustion engine. Therefore, it has been difficult to properly and strictly control the exhaust gas recirculation amount.
[0006]
Further, the unburned hydrocarbons HC, nitrogen oxides NO _X and sulfur oxides SO _X in the exhaust gas recirculation gas are enriched in tar by repeating the exhaust gas recirculation operation for a long time, and nitrogen monoxide NO and sulfur monoxide SO With the progress of oxidation of nitrogen, nitric oxide NO ₃ , nitric acid HNO ₃ , sulfur trioxide SO ₃ , sulfuric acid H ₂ SO _4, etc. are generated, and the parts of the exhaust gas recirculation path, cylinder walls, pistons, and piston rings are corroded, Moreover, the alkali value of the lubricating oil is reduced by the nitric acid HNO ₃ and the sulfuric acid H ₂ SO ₄ , so that the oil is easily oxidized and the performance of the oil is deteriorated.
[0007]
There has been a nitrogen-enriched combustion apparatus (Japanese Patent Laid-Open No. 2002-12049) that separates and removes a part of oxygen in the air and supplies nitrogen-enriched air to a combustion chamber.
[0008]
In the internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 2002-122049, since the nitrogen-enriched air is mixed with exhaust gas recirculation and supplied to the combustion chamber, the problem of exhaust gas recirculation is completely eliminated. It cannot be eliminated, and no consideration is given to how to set the nitrogen content of the nitrogen-enriched air in accordance with the air-fuel ratio or fuel supply amount. It was difficult to prevent the generation beforehand, and it was not possible to sufficiently reduce the emission of air pollutants such as nitrogen oxides and sulfur oxides.
[0009]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-122049 (FIGS. 1 and 2)
[0010]
[Problem to be solved]
The present invention relates to an improvement of an in-vehicle internal combustion engine that solves such a problem, and supplies nitrogen-enriched air having an appropriate nitrogen content to a combustion chamber of the internal combustion engine in accordance with a supply amount of a fuel. An object of the present invention is to provide an internal combustion engine having a nitrogen-enriched combustion function in which generation of oxides is suppressed as much as possible.
[0011]
Means and effects for solving the problem
The invention of the present application has solved such a problem, and an invention according to claim 1 is an in-vehicle internal combustion engine that operates at an air-fuel ratio larger than a stoichiometric air-fuel ratio, which is disposed in an exhaust passage and has A catalyst for purifying pollutants, a nitrogen-enriched air generating means for removing a part of oxygen in the air to generate a nitrogen-enriched air having a high nitrogen content, and a unit supplied to a combustion chamber of an internal combustion engine. A fuel supply amount measuring means for measuring a fuel supply amount per time; and a necessary oxygen amount per unit time required for sufficiently burning the fuel of the supply amount measured by the fuel supply amount measuring means, and Nitrogen-enriched air supply control means for controlling the supply of the nitrogen-enriched air in an amount substantially coincident with the required oxygen amount per unit time so as to conform to the air-fuel ratio. is there.
[0012]
Since the invention according to claim 1 is configured as described above, oxygen O ₂ in the nitrogen-enriched air supplied into the combustion chamber chemically reacts with the fuel supplied into the combustion chamber without excess or deficiency. the raised, fuel is substantially completely burned, the excess of residual oxygen O ₂ is no throat exist N殆. Therefore, nitrogen oxides and sulfur oxides generated during combustion can be suppressed, and the oxygen content in the exhaust gas can be reduced, so that highly efficient catalyst purification can be realized.
[0013]
Excess O ₂ under the current stoichiometric air-fuel ratio is about 1 vol% or less (excess O ₂ under lean burn is about 5 vol%) or more. The SULV standard can be cleared. Therefore, the current expensive CAT is not required, and the cost can be greatly reduced.
[0014]
According to the first aspect of the present invention, the excess oxygen O ₂ does not exist, and even if the excess oxygen O ₂ exists, the amount thereof is small. Maintained at a high level.
[0015]
Further, since the operation is performed at an air-fuel ratio larger than the stoichiometric air-fuel ratio, especially in a low-load operation state, pumping loss due to the throttle valve is small, and heat loss is reduced due to a decrease in combustion temperature, so that good fuel efficiency can be obtained. .
[0016]
Furthermore, since there is no need to perform exhaust gas recirculation, and even if exhaust gas recirculation is performed, combustion takes place in an environment where there is no excess O _2, so that corrosive substances themselves in the exhaust gas recirculated gas are drastically reduced. Accordingly, corrosion of exhaust gas catalyst components such as a cylinder wall, a piston, and a piston ring and deterioration of oil are suppressed.
[0017]
Further, in the invention according to claim 2, the nitrogen-enriched air having a constant maximum nitrogen content is generated by the nitrogen-enriched air generating means having a constant nitrogen content, and the nitrogen-enriched air having the constant nitrogen content is generated by the dilution means. Since the nitrogen-enriched air is diluted into the nitrogen-enriched air having a required nitrogen content, the nitrogen-enriched air suitable for the actual operating air-fuel ratio between the stoichiometric air-fuel ratio and the maximum air-fuel ratio is supplied to the combustion chamber of the internal combustion engine. Can be easily supplied.
[0018]
Further, according to the third aspect of the present invention, the dilution means can be simply and easily configured at low cost.
[0019]
Furthermore, in the invention according to claim 4, nitrogen-enriched air can be easily generated by a gas separation device having a simple structure.
[0020]
Moreover, in the invention according to claim 5, it is possible to activate the molecular motion of oxygen molecules O ₂ and nitrogen molecules N ₂ in the air supplied to the gas separation device, and to enhance the separation capability of the gas separation membrane. Therefore, the pressure of the air supplied to the gas separation device can be reduced to reduce the power (energy) required for separation, such as by operating the gas separation device, and in a nitrogen-enrichment device having the same discharge capacity. Space saving and miniaturization can be achieved.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention shown in FIGS. 1 and 2 will be described.
[0022]
An internal combustion engine 1 mounted on a passenger car (not shown) is a spark ignition type 4-stroke cycle internal combustion engine using gasoline as a fuel, and a piston 4 is slidable in a cylinder hole 3 of a main body 2 of the internal combustion engine 1. The piston 4 is connected to a crankshaft 6 via a connecting rod 5, and an intake port 8 and an exhaust port 9 communicating with a combustion chamber 7 located at the top of the cylinder hole 3 are connected to the top of the main body 2. The intake port 8 and the exhaust port 9 are respectively provided with an intake valve 10 and an exhaust valve 11 so as to be openable and closable, and an intake cam 12 and an exhaust cam 13 are provided above the intake valve 10 and the exhaust valve 11, respectively. The intake cam 12 and the exhaust cam 13 are connected to the crankshaft 6 via a transmission mechanism (not shown). The intake valve 10 and the exhaust valve 11 are driven to open and close at required timing by the intake cam 12 and the exhaust cam 13 which are driven to rotate, and a mixture of intake air and fuel is supplied into the combustion chamber 7. The air-fuel mixture in the combustion chamber 7 is ignited and burned by an ignition plug 14 provided in the combustion chamber 7, and the expansion of the combustion gas pushes down the piston 4 to rotate the crankshaft 6. A passenger car (not shown) can be driven by the rotary drive.
[0023]
Further, a fuel injection valve 17 is provided in an intake passage 15 communicating with the intake port 8, and the fuel injection valve 17 is connected to a fuel pump 20 in a fuel tank 19 via a fuel supply pipe 18. The fuel in the fuel tank 19 is sent by the fuel pump 20 to the fuel injection valve 17 via the fuel supply pipe 18, and a required amount of fuel is introduced into the intake passage 15 in accordance with an injection signal from a control unit (not shown). It is to be injected. A fuel gauge 21 is interposed in the fuel supply pipe 18, and the fuel injection amount in the fuel tank 19 is measured by the fuel gauge 21.
[0024]
Further, in the intake passage 15, a PB sensor 22 for detecting intake negative pressure is installed upstream of a location where the fuel injection valve 17 is installed, and a main throttle valve 23 and an intake air amount are measured toward the upstream thereof. An air flow meter 24 and a sub-throttle valve 25 are sequentially installed at a predetermined interval, and an upstream end of the intake passage 15 is connected to an exhaust side of an air cleaner 26 that filters intake air.
[0025]
Further, an upstream end of a bypass passage 27 is connected to the exhaust side of the air cleaner 26, and a downstream end of the bypass passage 27 is connected to the intake passage 15 between the main throttle valve 23 and the air cleaner 26. In the bypass passage 27, from the upstream end to the downstream end, the intake passage of the heat exchanger 28, the turbo pump of the supercharger 29, the nitrogen-enriched air generating unit 30, and the buffer tank 31 , A nitrogen-enriched air throttle valve 35 are sequentially provided.
[0026]
An exhaust passage 16 communicating with the exhaust port 9 includes a turbine of the supercharger 29, a linear AF sensor 32 for measuring an air-fuel ratio, an O ₂ sensor 33 for detecting oxygen O _{2 in} exhaust gas, A source catalyst 34 and an exhaust passage of the heat exchanger 28 are interposed.
[0027]
The nitrogen-enriched air generation unit 30 is a unit in which a large number of polyimide resin hollow fibers having an outer diameter of 400 μm (inner diameter of 200 μm) and a tube thickness of 100 μm are bundled and stored in a tubular body. The filtered air is heat-exchanged in the heat exchanger 28 with exhaust gas having a high temperature of about 300 ° C. flowing through the exhaust passage 16, heated to a high temperature, and rotated by the exhaust gas flowing through the exhaust passage 16. The air heated and pressurized to a high temperature and a high pressure while passing through the central hole of the polyimide resin hollow fiber has a molecular diameter smaller than the nitrogen molecule N ₂ while being pressurized by a turbo pump connected to the turbine of the above. towards the oxygen molecule O ₂ is, I to pass through many the polyimide resin hollow fiber wall, from the distal end of the polyimide resin hollow fiber, high nitrogen-enriched air having a nitrogen content flows To have.
[0028]
The nitrogen-enriched air flowing out of the nitrogen-enriched air generating unit 30 is stored in a buffer tank 31, merges with the air flowing through the intake passage 15, and is supplied to the combustion chamber 7.
[0029]
In a high-load operation state in which the operation is performed at a stoichiometric air-fuel ratio of 14.8, all of the 21% oxygen O ₂ contained in the air undergoes a chemical reaction with the fuel and burns. Since there is almost no excess oxygen O ₂ , the generation of nitrogen oxides is suppressed, but the air-fuel ratio is larger than the stoichiometric air-fuel ratio in which excess air is supplied to reduce the pumping loss of the internal combustion engine under low load operation. in a low load operating state, as a result of air than the stoichiometric air-fuel ratio 14.8 is supplied to the surplus, excess oxygen O ₂ which can not cause the fuel and chemical reaction occurs, which upon combustion, in the air It reacts with nitrogen N ₂ to cause generation of nitrogen oxides.
[0030]
In order to remove the excess oxygen O ₂ in the operating state of large air-fuel ratio than the stoichiometric air-fuel ratio, when the nitrogen-enriched air generating unit 30 to generate a nitrogen-enriched air with a reduced oxygen content, maximum air When There eg, 21, the intake air amount to be supplied to the internal combustion engine becomes a 21 / 14.8 ≒ 1.4 times, of the oxygen content 21% air to remove the excess oxygen _{O 2,} 0.21 /1.4≒0.15=15%, that is, the nitrogen-enriched air having a nitrogen content of 85% may be generated by the nitrogen-enriched air generating unit 30, and the nitrogen-enriched air throttle valve 35 and the bypass By controlling the adjusting means such as a valve (not shown) in the passage 27 by a computer (not shown) and appropriately adjusting the temperature, pressure and flow rate of the air supplied to the nitrogen-enriched air generating unit 30, the 85% nitrogen Nitrogen-enriched air chromatic rate is configured to obtain.
[0031]
At an air-fuel ratio of 21 or less, the opening degree of the sub-throttle valve 25 and the air cleaner 26 is appropriately adjusted, and the filtered air from the air cleaner 26 is added to the nitrogen-enriched air having a nitrogen content of 85%. as diluted nitrogen-enriched air nitrogen content of surplus oxygen O ₂ is not present, so as to control by a not shown computer.
[0032]
Further, if the excess oxygen O ₂ in the exhaust by the O ₂ sensor 33 is detected, and controls the opening degree of the main throttle valve 23 by the control signal of the computer in response to the detected excess amount of oxygen .
[0033]
An example of control of the sub-throttle valve 25 and the nitrogen-enriched air valve 35 by the electronic control unit ECU will be described with reference to a control system block diagram shown in FIG.
The electronic control unit ECU determines a fuel injection amount f based on the operation state of the internal combustion engine 1 and an air-fuel ratio (A / F) determination based on the operation state. In the electronic control unit ECU, the required intake flow rate Q is calculated by the intake flow rate calculating means 53 from the fuel injection amount f and the air-fuel ratio α determined by the determining means 51 and 52.
[0034]
On the other hand, from the air-fuel ratio α determined by the air-fuel ratio (A / F) determining means 52, the corresponding nitrogen content Pn is calculated by the nitrogen content calculating means 54.
When the air-fuel ratio α is the stoichiometric air-fuel ratio 14.8, the nitrogen content Pn is 79%, and when the air-fuel ratio α is 21, the nitrogen content Pn is 85%. Assuming that α and the nitrogen content Pn are in a proportional relationship, the nitrogen content Pn when the air-fuel ratio α is between 14.8 and 21 can be calculated.
[0035]
When the nitrogen content Pn is obtained by the nitrogen content calculation means 54, the ratio β of the nitrogen-enriched air flow rate to the total intake flow rate Q can be calculated from the nitrogen content Pn. Calculate.
[0036]
Assuming now that the nitrogen-enriched air flow rate is qn and the normal air flow rate is qo, Q = qo + qn, and the following equation holds.
β = qn / (qo + qn)
Pn = (0.79 · qo + 0.85 · qn) / (qo + qn)
[0037]
Eliminating qo and qn from the above equations, the nitrogen-enriched air flow rate β becomes
β = (Pn−0.79) / (0.85−0.79) = (Pn−0.79) /0.06
It becomes.
[0038]
From the intake air flow rate Q obtained by the intake air flow rate calculation means 53 and the nitrogen-enriched air flow rate ratio β obtained by the nitrogen-enriched air flow rate calculation means 55, the nitrogen-enriched air flow rate calculation means 56 makes a nitrogen-enriched air flow rate qn = βQ. Is calculated, and the normal air flow rate calculating means 57 calculates the normal air flow rate qo = (1−β) Q.
[0039]
The opening degree θn of the nitrogen-enriched air throttle valve 35 for realizing the calculated nitrogen-enriched air flow rate βQ is calculated based on the intake negative pressure PB detected by the PB sensor 22 using the nitrogen-enriched air throttle valve opening degree calculating means 58. Is calculated.
[0040]
Similarly, the opening degree θo of the sub-throttle valve 25 for realizing the normal air flow rate (1−β) Q calculated by the normal air flow rate calculation means 57 is calculated based on the intake negative pressure PB. Is calculated.
[0041]
The nitrogen-enriched air throttle valve drive control means 60 controls the nitrogen-enriched air throttle valve 35 with the calculated nitrogen-enriched air throttle valve opening θn as the target value, and sets the calculated sub-throttle valve opening θo as the target value. The sub throttle valve drive control means 61 controls the sub throttle valve 25 as a value.
[0042]
The control of the nitrogen-enriched air throttle valve 35 and the sub-throttle valve 25 by the nitrogen-enriched air throttle valve drive control means 60 and the sub-throttle valve drive control means 61 is performed based on the target value based on the intake flow rate measured by the air flow meter 24. The feedback control is performed so as to match with.
[0043]
In the above control example, the nitrogen-enriched air obtained by the nitrogen-enriched air generating unit 30 is assumed to have a constant nitrogen content of 85%. If the nitrogen content fluctuates, if the fluctuated nitrogen content r can be detected. The nitrogen-enriched air flow ratio β calculated by the nitrogen-enriched air flow ratio calculating means 55 may be obtained from the following equation.
β = (Pn−0.79) / (r−0.79)
[0044]
The main throttle valve 23 is controlled by calculating the valve opening based on the operating state and the value detected by the O ₂ sensor 33.
[0045]
Since the embodiment shown in FIG. 1 is configured as described above, when the operation is performed at the stoichiometric air-fuel ratio of 14.8, the following operation is performed.
[0046]
First, the nitrogen-enriched air throttle valve 35 is closed, and the sub-throttle valve 25 is fully opened. The injection amount of fuel injected from the fuel injection valve 17 is calculated by the fuel meter 21, and the main throttle valve 23 is adjusted so that the intake air amount measured by the air flow meter 24 becomes 14.8 times the fuel injection amount. Is adjusted by a computer (not shown), the oxygen O ₂ in the air supplied into the combustion chamber 7 of the internal combustion engine 1 reacts entirely with the fuel injected from the fuel injection valve 17 to generate generation of nitrogen oxides by the reaction of excess oxygen O ₂ is Donaku N殆, this excess oxygen O ₂ and nitrogen N ₂ is suppressed to.
[0047]
Moreover, the excess oxygen O ₂ in the exhaust gas described above, to be detected by the O ₂ sensor 33, the opening degree of the O ₂ main throttle valve 23 by the corresponding computer to the detection signal of the sensor 33 is controlled, excess Generation of nitrogen oxides NO _X by oxygen O ₂ is more reliably controlled.
[0048]
Further, when the operation is performed at the maximum air-fuel ratio 21, if the sub-throttle valve 25 is closed and the nitrogen-enriched air throttle valve 35 is fully opened, the clean intake air filtered by the air cleaner 26 is sent to the heat exchanger 28. The heat is exchanged with the exhaust gas in the exhaust passage 16 having passed through the three-way catalyst 34 in the heat exchanger 28, and the supercharger 29 is rotated by the exhaust gas flowing into the exhaust passage 16 from the exhaust valve 11. The turbo pump of the supercharger 29 is driven by the turbine, and the high-temperature clean air is pressurized and supplied to the nitrogen-enriched air generating unit 30.
[0049]
Oxygen O ₂ in the high-temperature and high-pressure clean air supplied to the nitrogen-enriched air generating unit 30 is partially removed by the nitrogen-enriched air generating unit 30 to provide a nitrogen-enriched air having a nitrogen content of 85%. The nitrogen-enriched air flows through the downstream portion of the bypass passage 27 via the buffer tank 31, passes through the intake port 8 from the downstream portion of the intake passage 15, and flows with the fuel injected from the fuel injection valve 17. Oxygen O ₂ in the nitrogen-enriched air flowing into the combustion chamber 7 reacts without exhaustion with the fuel, and the fuel burns almost completely, so that the excess oxygen O ₂ in the exhaust gas decreases. As a result, the generation of nitrogen oxides NO _X due to the exhaust purification excess oxygen O ₂ is suppressed, and the exhaust purification by the three-way catalyst 34 is performed almost completely.
[0050]
Further, compared with the case where the operation is performed at the stoichiometric air-fuel ratio, since a large flow rate of the nitrogen-enriched air is supplied into the combustion chamber 7, the pumping loss is reduced, and the heat loss is reduced due to a decrease in the combustion temperature. In addition, fuel efficiency in a low load operation state is improved.
[0051]
In addition, compared to air, the proportion of triatomic molecules in the exhaust gas is higher, which increases the specific heat, thereby increasing the proportion of gas stored as internal energy. Decrease.
[0052]
Further, the specific heat ratio of the exhaust gas recirculated gas to which the combustion exhaust gas is added is 1.1 to 1.2, whereas the specific heat ratio of the nitrogen-enriched air in the present embodiment is 1.4. However, fuel economy can be improved.
[0053]
Further, the clean intake air supplied to the nitrogen-enriched air generating unit 30 is exchanged with the exhaust gas flowing through the exhaust passage 16 in the heat exchanger 28 and is heated to a high temperature. As a result, the oxygen removal efficiency of the nitrogen-enriched air generation unit 30 is improved, the supply pressure to be applied to the clean intake air supplied into the nitrogen-enriched air generation unit 30 is reduced, and the nitrogen enrichment is reduced. The air separation flow rate increases.
[0054]
Next, when the operation is to be performed at an air-fuel ratio intermediate between the stoichiometric air-fuel ratio 14.8 and the maximum air-fuel ratio 21, the sub-throttle valve 25 and the nitrogen-enriched air throttle valve are controlled based on a control signal from a computer (not shown). If the opening degree of 35 is set to an optimum value, nitrogen-enriched air having a nitrogen content suitable for the intermediate air-fuel ratio is supplied to the combustion chamber 7 and no excess oxygen O ₂ remains in the combustion chamber 7. As a result, the injected fuel in the combustion chamber 7 can be completely burned, the generation of nitrogen oxides NO _X can be suppressed, and the exhaust gas can pass through the three-way catalyst 34 without excess oxygen O _2. , can be performed outside of the nitrogen oxides NO _X the three way catalyst 34 at a high level of carbon monoxide CO, and the exhaust gas purification to remove unburned hydrocarbons HC.
[0055]
Further, in the case of a rapid change in the air-fuel ratio or a sudden change in the supply amount of the nitrogen-enriched air, the sudden change in the supply amount of the nitrogen-enriched air is controlled by the nitrogen-enriched air stored in the buffer tank 31. Can be.
[0056]
In the above-described embodiment, the fuel is injected from the fuel injection valve 17 to the intake port 8. However, the present invention is applied to a direct injection spark ignition type internal combustion engine in which the fuel is directly injected into the combustion chamber 7 from the fuel injection valve 17. Can also be applied.
[0057]
In the above-described embodiment, the spark ignition type internal combustion engine uses gasoline as fuel. However, the invention can be applied to a compression ignition type diesel engine using light oil as fuel.
[0058]
Further, the present invention can be applied to an internal combustion engine using methane (natural gas), methanol, or hydrogen as a fuel in addition to petroleum such as gasoline and light oil.
[0059]
Further, the nitrogen-enriched air generating unit 30 of the above embodiment is a unit in which a large number of polyimide resin hollow fibers are bundled and stored in a cylindrical body, but two silicone rubber flat membranes are parallel to each other. A large number of separation membrane units, each of which is held at a predetermined interval, are arranged at predetermined intervals, communicate with each other in the separation membrane units, and pressurize clean air into the separation membrane units to remove oxygen O ₂ . It may be one that separates and removes a part to separate and generate nitrogen-enriched air, or an electrolyte-separated nitrogen that conducts and separates by applying a voltage to the solid electrolyte layer and ionizing oxygen O ₂ in the air with electric energy. It may be an enriched air generation unit, or may be another type of separation device.
[0060]
Further, in the above-described embodiment, the O ₂ sensor 33 is arranged on the upstream side of the three-way catalyst 34, but the O ₂ sensor 33 may be arranged on the downstream side of the three-way catalyst 34, or both upstream side and downstream side may be disposed an O ₂ sensor 33.
[0061]
Furthermore, a cooler may be provided in the buffer tank 31, or a cooler may be provided instead of the buffer tank 31, and the high-temperature nitrogen-enriched air discharged from the nitrogen-enriched air generating unit 30 is cooled by the cooler, The charging efficiency of the internal combustion engine 1 and, consequently, the fuel efficiency can be improved.
[0062]
Moreover, in the above-described embodiment, the clean air supplied to the nitrogen-enriched air generating unit 30 is heated by the exhaust heat via the heat exchanger 28, but the clean air is cooled by the engine cooling water or the air passing through the radiator. It may be heated.
[0063]
Although the turbocharger is used in the above embodiment to pressurize the air supplied to the nitrogen-enriched air generating unit 30, the compressor driven by the compressor or the motor connected to the internal combustion engine 1 uses the turbocharger. Machine may be used.
[0064]
Further, a compressor may be provided upstream of the intake passage 15 to supply compressed air to the intake passage.
[0065]
Furthermore, EGR may be used in combination with the present embodiment.
[Brief description of the drawings]
FIG. 1 is an explanatory view illustrating a position embodiment of a vehicle-mounted internal combustion engine with a nitrogen-enriched combustion function according to the present invention.
FIG. 2 is a control system block diagram showing an example of control in the embodiment shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Body, 3 ... Cylinder hole, 4 ... Piston, 5 ... Connecting rod, 6 ... Crankshaft, 7 ... Combustion chamber, 8 ... Intake port, 9 ... Exhaust port, 10 ... Intake valve, 11 ... Exhaust valve, 12 ... intake cam, 13 ... exhaust cam, 14 ... spark plug, 15 ... intake passage, 16 ... exhaust passage, 17 ... fuel injection valve, 18 ... fuel supply pipe, 19 ... fuel tank, 20 ... fuel pump, Reference Signs List 21 fuel meter, 22 PB sensor, 23 main throttle valve, 24 air flow meter, 25 auxiliary throttle valve, 26 air cleaner, 27 bypass passage, 28 heat exchanger, 29 turbocharger, 30 nitrogen-enriched air generation unit, 31 ... buffer tank, 32 ... linear AF sensor, 33 ... _{O 2} sensor, 34 ... three-way catalyst, 35 ... nitrogen-enriched air throttle valve 36 ... oxygen-enriched air outlet hole,
51: fuel injection amount determining means, 52: air-fuel ratio (A / F) determining means, 53: intake flow rate calculating means, 54: nitrogen content calculating means, 55: nitrogen-enriched air flow rate calculating means, 56: nitrogen rich Calculated air flow rate calculation means, 57: Normal air flow rate calculation means, 58: Nitrogen-enriched air throttle valve opening degree calculation means, 59: Sub-throttle valve opening degree calculation means, 60: Nitrogen-enriched air throttle valve drive control means, 61 ... Auxiliary throttle valve drive control means.

Claims (5)

In an in-vehicle internal combustion engine that operates with an air-fuel ratio larger than the stoichiometric air-fuel ratio,
A catalyst disposed in the exhaust passage to purify pollutants in exhaust gas;
A nitrogen-enriched air generating means for removing a part of oxygen in the air to generate a nitrogen-enriched air having a high nitrogen content,
Fuel supply amount measuring means for measuring a fuel supply amount per unit time supplied into the combustion chamber of the internal combustion engine,
The required amount of oxygen per unit time required to burn the fuel of the supply amount measured by the fuel supply amount measuring means is calculated, and the required amount of oxygen per unit time is substantially reduced so as to conform to a predetermined air-fuel ratio. A nitrogen-enriched air supply control means for controlling the supply of the same amount of the nitrogen-enriched air. The nitrogen content of the nitrogen-enriched air generated by the nitrogen-enriched air generating means is set to a maximum nitrogen content at which the fuel can be completely burned without generating excess oxygen at the maximum air-fuel ratio,
When the internal combustion engine is operated at an air-fuel ratio lower than the maximum air-fuel ratio, nitrogen-enriched air having a nitrogen content sufficient to supply a substantially necessary amount of oxygen at the low air-fuel ratio by adding air. 2. A vehicle-mounted internal combustion engine with a nitrogen-enriched combustion function according to claim 1, further comprising a diluting means for diluting the gas. The dilution means includes:
An upstream end is directly or indirectly connected to the atmosphere, and a downstream end is connected to a nitrogen-enriched air introduction passage leading to the combustion chamber from the nitrogen-enriched air generating means,
3. The on-vehicle internal combustion engine with a nitrogen-enriched combustion function according to claim 2, further comprising a ventilation amount adjusting valve for increasing or decreasing the ventilation amount of the bypass passage. 4. The on-vehicle vehicle with a nitrogen-enriched combustion function according to claim 2, wherein the nitrogen-enriched air generating means is a gas separation device for separating pressurized air having a pressure higher than the atmosphere by a separation membrane. Internal combustion engine. 5. The on-vehicle internal combustion engine with a nitrogen-enriched combustion function according to claim 4, further comprising heating means for heating the air guided to the gas separation device with heat generated during operation of the internal combustion engine.

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